                   {:finalize (cljs finalize-fn)}))))
 
 (defmethod load-slice "derived"
-  [slice concepts definition]
+           [slice concepts definition]
   (let [mr (derived-slice-map-reduce slice definition)
         slicedef (get-in definition [:slices (keyword slice)])
         fields (data/slice-columns slicedef)

  [slice definition]
  (let [sdef (get-in definition [:slices (keyword slice)])
        dataset (:database definition)
        
        from-collection (:slice sdef)
        to-collection slice
        to-zip-fn (field-zip-fn sdef)

              (assoc acc concept (read-concept-data concept definition)))
            {} (keys concepts))))

(defn- emit-post-load-sample
  [dataset slice]
  (let [result (data/get-find dataset slice {:limit 1 :query {} :fields {}})]
    (log/info "Slice loaded. " (:total result)  "records found. Sample record:" (:data result))
    ))

(defn- join-maps
  "Join two vectors of maps on a key."
  [left lkey lval right rkey rval]
